The zwitterions with small ΔED-A and large φDA have a small ΔEH-L of ca. 1 eV and show amphoteric redox properties and near-infrared (NIR) electronic absorption exceeding λ = 1000 nm. The NIR absorption responds to solvent polarity, temperature, and acid addition. This molecular design will generate small π-conjugated donor-acceptor molecules with small ΔEH-L values.Concentrations in GC-MS using electron-ionization mass spectrometry can be determined without pure calibration standards through prediction of relative total-ionization cross sections. An atom- and group-based artificial neural network (FF-NN-AG) model is created to generate EI cross sections and calibrations for organic compounds. This model is easy to implement and is more accurate than the widely used atom-additivity-based correlation of Fitch and Sauter (Anal. Chem. 1983). Ninety-two new measurements of experimental EI cross sections (70-75 eV) are joined with different interlaboratory datasets, creating a 396-compound cross-section database, the largest to date. The FF-NN-AG model uses 16 atom-type descriptors, 79 structural-group descriptors, and one hidden layer of 10 nodes, trained 500 times. In each cycle, 96% of the compounds in this database are freshly chosen at random, and then the model is tested with the remaining 4%. The resulting r2 is 0.992 versus 0.904 for the Fitch and Sauter correlation, root mean square deviation is 2.8 versus 9.2, and maximum relative error is 0.30 versus 0.73. As an example of the model's use, a list of cross sections is generated for various sugars and anhydrosugars.To develop thermoelectric devices, it is of the utmost importance to design organic building blocks to have efficient thermopower. Whereas conjugated and aromatic molecules with intrinsic narrow band gaps are attractive candidates to achieve efficient thermoelectric properties, saturated molecules are usually avoided owing to intrinsically poor thermopower. Here we demonstrate that thermopower of saturated molecules can be enhanced by superexchange coupling. Specifically, thermoelectric properties of large-area junctions that contain self-assembled monolayers of oligo(ethylene glycol) thiolates and alkanethiolates are compared. Through large-area thermopower measurements using a liquid metal top electrode, we show that the superexchange coupling enhances the Seebeck coefficient and counterintuitively leads to an increase in the Seebeck coefficient with increasing the length in a certain conformation. The improved thermoelectric performance is attributed to the superexchange-induced enhanced ability to mediate metal wave function in junctions. Our work offers new insights for improving the thermoelectric performance of nonconjugated, saturated molecules.A quantitative prediction of polymer-entangled dynamics based on molecular simulation is a grand challenge in contemporary computational material science. The drastic increase of relaxation time and viscosity in high-molecular-weight polymeric fluids essentially limits the usage of classic molecular dynamics simulation. Here, we demonstrate a systematic coarse-graining approach for modeling entangled polymers under the slip-spring particle-field scheme. Specifically, a frequency-controlled slip-spring model, a hybrid particle-field model, and a coarse-grained model of polystyrene melts are combined into a hybrid simulation technique. https://www.selleckchem.com/products/tak-875.html Via a rigorous parameterization strategy to determine the parameters in slip-springs from existing experimental or simulation data, we show that the reptation behavior is clearly observed in multiple characteristics of polymer dynamics, mean-square displacements, diffusion coefficients, reorientational relaxation, and Rouse mode analysis, consistent with the predictions of the tube theory. All dynamical properties of the slip-spring particle-field models are in good agreement with classic molecular dynamics models. Our work provides an efficient and practical approach to establish chemical-specific coarse-grained models for predicting polymer-entangled dynamics.Through the development of ligands and reaction conditions, the Rh(III)-catalyzed selective annulation of benzamides with internal alkynes has been achieved to the formation of O-cyclized isochromen-imines. Various substituents are well-tolerated under mild reaction conditions. Density functional theory calculations indicate that silver carbonate could act as a Lewis acid to assist the ligand to improve the chemical selectivity of the reaction in a catalytic system.Photothermal effects of metal nanoparticles (NPs) are used for various biotechnological applications. Although NPs have been used in a polymerase chain reaction (PCR), the effects of shape on the photothermal properties and its efficiency on PCR are less explored. The present study reports the synthesis of triangular gold and silver NPs, which can attain temperatures up to ?90 °C upon irradiation with 808 nm laser. This photothermal property of synthesized nanoparticles was evaluated using various concentrations, irradiation time, and power to create a temperature profile required for variable-temperature PCR. This study reports a cost-effective, machine-free PCR using both gold and silver triangular NPs, with efficiency similar to that of a commercial PCR machine. Interestingly, addition of triangular NPs increases PCR efficiency in commercial PCR reactions. The higher PCR efficiencies are due to the direct binding and unfolding of double-stranded DNA as suggested by circular dichroism and UV spectroscopy. These findings suggest that triangular NPs can be used to develop cost-effective, robust machine-free PCR modules and can be used in various other photothermal applications.The core electron binding energies (CEBEs) and core-level excitation energies of thymine, adenine, cytosine, and uracil are studied by the Kohn-Sham (KS) method with long-range corrected (LC) functionals. The CEBEs are estimated according to the Koopmans-type theorem for density functional theory. The excitation energies from the core to the valence π* and Rydberg states are calculated as the orbital energy differences between core-level orbitals of a neutral parent/cation and unoccupied π* or Rydberg orbitals of its cation. The model is intuitive, and the spectra can easily be assigned. Core excitation energies from oxygen 1s, nitrogen 1s, and carbon 1s to π* and Rydberg states, and the chemical shifts, agree well with previously reported theoretical and experimental data. The straightforward use of KS orbitals in this scheme carries the advantage that it can be applied efficiently to large systems such as biomolecules and nanomaterials.